Localization of the predicted peptide from isotig21532 in Onchocerca flexuosa by immunohistochemical labeling. Polyclonal antibodies raised against a predicted peptide from O. flexuosa with sequence similarity to a hypothetical protein from the Wolbachia endosymbiont of Onchocerca volvulus labeled the hypodermis, lateral, and median chords in the anterior half of male worms (A-C). Strong labeling was observed in the spermatogonia (A) and spermatocytes (B) in the testis, but not in mature spermatozoa within the vas deferens (C). Sexually immature (D) and older, microfilariae producing females both showed antibody labeling in the intestine, hypodermis, lateral chords, and median chords (G). In young females, intense labeling was seen on the inner and outer surfaces of the uterus (D). In older females, labeling was seen in the ovaries (E), oocytes (F), and early embryos (G, arrow) but not in uterus itself (G-I). The intensity of labeling decreased dramatically in morula stage embryos (G, arrowhead) but increased again in microfilariae (H, I). Abbreviations: cu, cuticle; hy, hypodermis; m, muscle; lc, lateral chords; mc, median chords; i, intestine; ut, uterus; utw, uterine wall; t, testis; vd, vas deferens. Scale bar = 50μm.